Migration from Cisco 1720 to Cisco 800 series

I have a business using 3 Cisco 1720 routers to connect two remote branches to the third main branch via T1.

I have never worked with Cisco routers apart from these, and the only thing I know how to do with the 1720's is backing up or loading their existing configurations using Cisco ConfigMaker.

The decision has been made to finally retire the outdated routers, despite continuing to function without issue since 2004. They want them replaced with a newer Cisco Router.

I have been led to believe, the current 800 series routers are what I need to be looking at to replace the 1720, but I haven't confirmed this to be true.

Can any of you Cisco guru's point me in the right direction as to what specific model and/or hardware configuration I need?

To help a little with answering my question, this is the existing setup:

the main branch router has two "WIC 1DSU T1" cards installed. One card is configured for one remote branch and the second card for the second remote branch. And of course each branch has a Cisco 1720 with the one of the same "WIC 1DSU T1" cards installed in order to communicate back to the main branch router.

I have provided the configurations for all three if that would assist in properly determining how things are setup and what new router/hardware configuration will work to replace the 1720's.

Thank you Soulja that is definitely what I need. Are the configurations transferable from the 1720's to the 1921's or will I have to figure out how to configure the new routers/find someone that knows how?